c70216390f
The tasks themselves now control whether they are executed again. To compare it to the old system, oneshot tasks now return `false` and repeating tasks return `true`. Letting the housekeeper remove the tasks makes the code simpler and removes the possibility of the task being removed while it is being executed. It does introduce a deadlock possibility if a housekeeper function is called inside a housekeeper task.
100 lines
2.3 KiB
C
100 lines
2.3 KiB
C
#pragma once
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/*
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* Copyright (c) 2016 MariaDB Corporation Ab
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*
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* Use of this software is governed by the Business Source License included
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* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
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*
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* Change Date: 2020-01-01
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*
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* On the date above, in accordance with the Business Source License, use
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* of this software will be governed by version 2 or later of the General
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* Public License.
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*/
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/**
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* @file housekeeper.h A mechanism to have task run periodically
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*/
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#include <maxscale/cdefs.h>
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#include <maxscale/dcb.h>
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MXS_BEGIN_DECLS
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/**
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* The task callback function
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*
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* The parameter is the user data given to the `hktask_add` function.
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*
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* If the function returns true, the same task is added back to the queue and
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* executed again at a later point in time. If the function returns false,
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* the task is removed.
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*/
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typedef bool (*TASKFN)(void *data);
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/**
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* Initialises the housekeeper mechanism.
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*
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* A call to any of the other housekeeper functions can be made only if
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* this function returns successfully.
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*
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* @return True if the housekeeper mechanism was initialized, false otherwise.
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*/
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bool hkinit();
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/**
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* Shuts down the housekeeper mechanism.
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*
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* Should be called @b only if @c hkinit() returned successfully.
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*
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* @see hkinit hkfinish
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*/
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void hkshutdown();
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/**
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* Waits for the housekeeper thread to finish. Should be called only after
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* hkshutdown() has been called.
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*/
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void hkfinish();
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/**
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* @brief Add a new task
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*
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* The task will be first run @c frequency seconds after this call is
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* made and will the be executed repeatedly every frequency seconds
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* until the task is removed.
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*
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* Task names must be unique.
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*
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* @param name Task name
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* @param task Function to execute
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* @param data Data passed to function as the parameter
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* @param frequency Frequency of execution
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*/
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void hktask_add(const char *name, TASKFN func, void *data, int frequency);
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/**
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* @brief Remove all tasks with this name
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*
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* @param name Task name
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*/
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void hktask_remove(const char *name);
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/**
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* @brief Show the tasks that are scheduled for the house keeper
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*
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* @param pDcb The DCB to send to output
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*/
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void hkshow_tasks(DCB *pdcb);
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/**
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* @brief Show tasks as JSON resource
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*
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* @param host Hostname of this server
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*
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* @return Collection of JSON formatted task resources
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*/
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json_t* hk_tasks_json(const char* host);
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MXS_END_DECLS
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